A conventional drip tape has a path along which water flows and the pressure-reducing means including an uneven surface part .
Typically, the drip tapes using the uneven surface part are classified into a tape provided with a pressure-reducing liner formed continuously, and a tape provided with pressure-reducing emitters which are arranged discontinuously (but are regularly arranged at predetermined intervals).
A representative example of the former was proposed in Korean Utility Model Registration No. 0411174 (Mar. 6, 2006), which was filed by the applicant of the present invention and entitled ┌HOSE USED FOR CROP CULTIVATION┘.
A representative example of the latter was proposed in Korean Patent Registration No. 0569225 (Apr. 3, 2006), which was filed by the applicant ‘Jae-yong So’ and entitled ┌PRESSURE-REDUCING HOSE┘.
As for a conventional drip hose having another structure, the hose has a pressure-reducing means which has repeatedly bent passages like the labyrinthine. A representative example of the drip hose using pressure-reducing means formed as the labyrinthine was proposed in Korean Patent Registration No. 0204261 (Mar. 26, 1999), which was filed by Rain Bird Sprinkler Manufacturing Corporation and entitled ┌DRIP IRRIGATION TUBE┘.
However, the gist of the drip tapes using the pressure-reducing means having the uneven surface or labyrinthine structure differs from that of the present invention.
Meanwhile, conventional techniques have tubes which are manufactured by heat-bonding overlapping films in the same manner as the present invention. The drip tubes were proposed in Korean Utility Model Registration No. 0172991 (Dec. 15, 1999), which was filed by the applicant
‘Kyu-Sub Choi’ and entitled ┌FILM HOSE FOR CROP CULTIVATION┘, in Korean Utility Model Registration No. 0306616 (Feb. 25, 2003), which was filed by the applicant ‘Ki-Seok Seo’ and entitled ┌DRIP TYPE WATER SUPPLY TUBE┘, and in Korean Utility Model Registration No. 0332247 (Oct. 27, 2003), which was filed by the applicant ‘Ho-Gyoun Kim’ and entitled ┌WATER SUPPLY HOSE FOR FARMING┘.
However, the conventional techniques proposed in the above Utility Models have a little pressure-reducing effect. In the conventional techniques, water is forcefully discharged from the tube so that a large amount of water does not permeate into the ground but flows along the ground surface, thereby causing soil erosion. Furthermore, uniform irrigation is not ensured along the entire tube.
According to a conventional technique, a hose has overlapping parts of films and protrusions maintaining the gap which are defined by the overlapping parts of the films in an outer water passage. Moreover, the gap is arranged in the longitudinal direction of the hose in order to discharge water evenly from the hose. The conventional tube was proposed in Korean Utility Model Registration No. 0401878 (Nov. 16, 2005), which was filed by the applicant ‘Gak-su Kwon’ and entitled ┌DRIP HOSE┘.
However, this Utility Model has nothing to do with dripping water evenly and continuously for the growth of plants.
In the technical field for drip tapes, there are similarities between the above-mentioned conventional techniques and the present invention. However, the drip tape of the present invention can control the pressure without using a pressure-reducing means such as an uneven surface or labyrinthine structure.
The drip tape of the present invention has overlapping sheets formed by overlapping parts of a film (or films). The overlapping sheets of the drip tape are expanded by water pressure. As a result, the pressure of the discharged water is reduced. These characteristics of the present invention are markedly different from those of the hoses of the conventional techniques.